The field of enzymatic detergent additives has been rapidly growing during the last decades. Reference is made to e.g., the article "How Enzymes Got into Detergents", Vol. 12, Developments in Industrial Microbiology, a publication of the Society for Industrial Microbiology, American Institute of Biological Sciences, Washington, D.C. 1971, by Claus Dambmann, Poul Holm, Villy Jensen and Mogens Hilmer Nielsen, and to the article "Production of Microbial Enzymes", Microbial Technology, Sec. Ed., Vol. I, Academic Press, 1979, pp. 281-311, by Knud Aunstrup, Otto Andresen, Edvard A. Falch and Tage Kjaer Nielsen. Inclusion of enzymes in detergent formulations is a long accepted practice.
The most common enzymatic detergent additive is a proteolytic additive, but also amylolytic, cellulolytic, and lipolytic detergent additives are contemplated by the art. See, for example, Great Britain Pat. No. 1,554,482, BE Pat. No. 888,632, and U.S. Pat. No. 4,011,169. Enzymes named above are not an exhaustive listing, but they represent the most common enzymatic additives used in commercial detergent compositions.
This invention is concerned exclusively with enzyme containing granulates used as detergent additives.
One of the most common commercially available forms of an enzymatic additive is the granulate form. For the purposes of this invention, a prilled product is considered a specially prepared granulate. These granulates can be produced in several different ways. Great Britain Pat. No. 1,362,365 describes the production of enzyme containing granulates used as detergent additives by means of an apparatus comprising an extruder and a spheronizer (sold as MARUMERIZER.RTM.), and U.S. Pat. No. 4,106,991, describes the production of enzyme containing granulates used as detergent additives by means of a drum granulator, both patents being incorporated herein by reference.
The granulate enzyme forms supplied by enzyme producers to the detergent industry have achieved market acceptance to such a degree that granulates substantially improved in some major characteristic e.g., in enzyme stability, are not likely to be accepted by the detergent industry if accompanied by any significant level of deterioration in the physical stability of the granule.
The object of this invention is to provide an enzyme containing granulate composition exhibiting improved enzyme stability and, in addition, the physical stability level to which the detergent art has become accustomed.
Other objects of this invention are set forth hereinafter.